The invention relates to a plug construction for an optical insert plug-and-socket connection which may be used to optically connect a daughters board to a mother board. To avoid unnecessary force transmission onto the daughter board and to compensating for mass tolerances, both boards in the connected condition are mechanically decoupled from one another.
It is therefore the object of the invention to provide a plug construction of the type mentioned above which even when significantly miniaturized ensures a reliable decoupling and which is easily assembled and simply manufactured. This object is achieved with a plug construction as described below.
We have found that with a leaf spring bent at an angle excellent results may be achieved. In particular the leaf spring permits a pivoting out downward which with regard to the lateral space requirement of the plug is not inhibiting. The leaf spring is preferably attached to the daughter board and the push abutment to the plug part. However, a kinematic reversal would also be conceivable, that is, attaching the leaf spring to the relatively displaceable plug part.
The push abutment may be formed by a material shoulder, wherein the angled part after rising over the material shoulder engages in a recess in which, in the insert direction, it can move a distance which corresponds to the maximum possible decoupling distance between the mother board and the daughter board. As the angled part dips into the recess, the leaf spring in the decoupled condition is again completely relaxed. It would, however, also be possible for the leaf spring in the decoupled condition to remain tensioned and for the angled part in this operating condition to be pressed against a surface of the plug part. The friction thus arising might be useful for braking the decoupling movement.
The material shoulder runs, preferably, roughly parallel to the angled part and roughly at a right angle to the insert direction. In spite of this construction of the material shoulder, the leaf spring with an increase of the push force is bent back because the angled part is itself subjected to bending forces. This construction of the material shoulder and the angled part has the advantage that the negotiation of the material shoulder is effected practically at a stroke, which simplifies the insert procedure. Alternatively, the angled part and/or the material shoulder could be oriented at an oblique angle to the insert direction, whereby the required push force for negotiating the material shoulder may be reduced.
The side of the recess which faces the material shoulder may be formed as a run-up ramp for the angled part on pulling back the plug from the socket part. This has the effect of reducing the necessary force for negotiating the material shoulder when the movement is reversed.
The leaf spring may be formed as a separate bent part of metal, having an anchor in the region of the fixation location. Providing a separate bent part has the advantage that the spring properties may be exactly matched to the concrete case. But it would also be possible to integrate the leaf spring directly into the daughter board or into a housing part attached to the board or into a plug housing, and to manufacture it of plastic material.
The leaf spring is advantageously held in an insert housing which forms at least one guide passage for the plug part. Further advantages may now result because the insert housing is displaceably mounted in a limited manner relative to the daughter board on a plane running roughly at right angles to the plane of the daughter board and to the insert direction. This floating mounting has the advantage that although in two spatial axes a compensation of mass inaccuracies is possible, this is not possible in the insert direction. This compensation possibility avoids a jamming of the plug parts.
The plug housings must, in the latch-in position, be held pull-proof in the socket part. This is effected by providing resilient locking elements which are arranged on the plug housing and which in the latch-in position are latchable in a detent on the socket part. To unlatch, a lifting out of the detent is necessary. With individual plug-and-socket connections this movement is carried out manually on a suitable grip piece; details may be deduced from European Patent Publication 1072920. However, with insert plug-and-socket connections with several plugs lying next to one another, this is difficult, and the unlocking movement or the force required is advantageously derived from the withdrawal movement of the plug. For this the locking element comprises a lever arm which cooperates with at least one guiding slide on the insert housing such in a way that on pulling back the plug housing, the locking is releasable. Such a controlled unlocking movement may also be realized on insert plug-and-socket connections with conventional insert elements.
The locking element may be formed as a two-arm lever which is releasably fixable on the plug housing, wherein on one lever arm there is at least one detent pawl which cooperates with the undercut and on the other lever arm there is at least one guide element which cooperates with the guiding slide. The lever releasably fixed on the plug housing has the advantage that conventional plug housings for the use in an insert plug-and-socket connection may be retrofitted.
The guiding slide may be a ramp arranged on a lateral wall of the guide passage. The ramp may run linearly or arcuately.
The guide passage may be covered with a releasable covering which comprises a centering element cooperating with a corresponding centering element on the socket part. The separate covering simplifies both the manufacture of the insert housing and the assembly of the individual plug parts in the guide passages. The construction of the centering element on the covering is above all advantageous.
The socket part has at least one socket opening which is closed by a pivotable protective flap which is linked on by a pivot pin going through the socket housing and the protective flap. Other linkage connections would of course be conceivable, but the pivot pin has the advantage that it may simultaneously accommodate a spring for biasing the protective flap toward the closure position. To fix the pivot pin laterally in the region of each protective flap, a circumferential groove is provided. A spur on the protective flap in the region of the deflection engages into this groove and thus fixes the pivot pin. This is possible because the protective flap for its part is laterally limited in the socket housing. Such a fixation of the socket flaps may also be applied to a conventional socket part for insert plug-and-socket connections or also for individual plug-and-socket connections.